Authors:C. González-Gómez, J. López-González, and M-A. Ferro-García
In the present work a study was made for determining colour intensities using as luminous non-monochromatic source the Cherenkov
emission produced in the walls of a glass capillary which acts as luminous source itself inside of a coloured solution to
be evaluated. The reproducibility of this method has been compared with the spectrophotometric assay; the relative errors
of both analytical methods have been calculated for different concentrations of congo red solution in the range of minimal
error, according to Ringbom's criterion. The sensitivity of this analytical method has been studied for the two β-emitters
Authors:M. Azahra, J. López-Peñalver, M. Camacho-García, C. González-Gómez, T. El Bardouni, and H. Boukhal
Aerosols samples in near-surface air of Granada (Spain) were collected on a weekly basis. The seasonal 210Pb and 7Be concentrations were determined during the five-year period, from October 1993 to September 1997. The elements, despite their different origin and their different distribution throughout the atmosphere, present the same seasonal variation. There was a tendency for a maximum during the summer season and a minimum during fall and/or winter. In this work, the concentration of 7Be and 210Pb and meteorological data have been used in order to determine the periods of the potential radioactive pollution. This study, also, shows that the deposition of 7Be occurs primarily by precipitation except during the investigation periods where precipitation was scarce and irregular.
Authors:A. González Arias, C. Torres, C. de Francisco, J. Muñoz, P. Hernández Gómez, O. Alejos, O. Montero, and J. Iñiguez
The article discusses theory and experiment about the measurement of
defect concentration in Ti-substituted yttrium iron garnet by means of thermogravimetry
techniques. The two possible cases arising from oxygen interchange with atmosphere,
oxygen vacancies and interstitial cations, may be analyzed quantitatively
from the derived expressions. The possibility of another type of defects being
present in the samples, not associated to oxygen evolution, is not excluded.
Measurements were carried out in air and CO2 for different
Ti contents. The substitution tends to increase slightly the defect parameter
θ in YIG, while a CO2 reducing atmosphere is
much more effective than the Ti substitution for increasing θ. Calculations
for a given single-phased sample sintered in air show two possibilities: a
deficit of one oxygen atom for every 2.5 unit cells of 96 atoms, or one excess
cation for every 3.5 cells. Other samples show very similar results. The accuracy
involved in the measurements is about 2–3%.